JOLLEGS 


UNIVERSITY  OF  CALIFORNIA  PUBLICATIONS 


COLLEGE  OF  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 


New  Control  Methods 


Pear  Thrips  and  Peach  Tree  Borer 


Earl  L.  Morris 


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BULLETIN  No.  228 

(Berkeley,  Cal.) 


SACRAMENTO 

Friend  Wm.  Richardson     -     -     Superintendent  of  State  Printing 

1912 


Benjamin  Ide  Wheeler,  President  of  the  University. 

EXPERIMENT  STATION  STAFF. 

E.  J.  Wickson,  M.A.,  Director  and  Horticulturist. 

E.   W.  Hilgard,  Ph.D.,  LL.D.,  Chemist   (Emeritus). 

W.  A.  Setchell,  Ph.D.,  Botanist. 

Leroy  Anderson,  Ph.D.,  Dairy  Industry  and  Superintendent  University  Farm  Schools. 

M.  E.  Jaffa,  M.S.,  Nutrition  Expert. 

R.  H.  Loughridge,  Ph.D.,  Soil  Chemist  and  Physicist  (Emeritus). 

C.  W.  Woodworth,  M.S.,  Entomologist. 

Ralph  E.   Smith,  B.S.,  Plant  Pathologist  and  Superintendent  of  Southern  California 

Pathological  Laboratory  and  Experiment  Station. 
G.  W.  Shaw,  M.A.,  Ph.D.,  Experimental  Agronomist  and  Agricultural  Technologist,  in 

charge  of  Cereal  Stations. 

E.  W.  Major,  B.Agr.,  Animal  Industry. 

B.  A.  Etcheverrt,  B.S.,  Irrigation  Expert. 

F.  T.  Bioletti,  B.S.,  Viticulturist. 

W.  T.  Clarke,  B.S.,  Assistant  Horticulturist  and  Superintendent  of  University  Exten- 
sion in  Agriculture. 

John  S.  Burd,  B.S.,  Chemist,  in  charge  of  Fertilizer  Control. 

J.  E.  Coit,  Ph.D.,  Assistant  Pomologist,  in  charge  of  the  Citrus  Experiment  Station, 
Riverside. 

George  E.  Colby,  M.S.,  Chemist  (Fruits,  Waters  and  Insecticides),  in  charge  of 
Chemical  Laboratory. 

H.  J.  Quayle,  M.S.,  Assistant  Entomologist. 

H.  M.  Hall,  Ph.D.,  Assistant  Botanist. 

C.  M.  Haring,  D.V.M.,  Assistant  Veterinarian  and  Bacteriologist. 
E.  B.  Babcock,  B.S.,  Assistant  Agricultural  Education. 

W.  B.  Herms,  M.A.,  Assistant  Entomologist. 

W.  T.  Horne,  B.S.,  Assistant  Plant  Pathologist. 

C.  B.  Lipman,  Ph.D.,  Soil  Chemist  and  Bacteriologist. 

A.  J.  Gaumnitz,  Assistant  Agronomist,  University  Farm,  Davis. 
N.  D.  Ingham,  B.S.,  Assistant  in  Sylviculture,  Santa  Monica. 

T.  F.  Hunt,  B.S.,  Assistant  Plant  Pathologist. 

P.  L.  McCreary,  B.S.,  Chemist  in  Fertilizer  Control. 

E.  H.  Hagermann,  Assistant  in  Dairying,  Davis. 

R.  M.  Roberts,  Farm  Manager,  University  Farm,  Davis. 

B.  S.  Brown,  B.S.A.,  Assistant  Horticulturist,  University  Farm,  Davis. 
J.  I.  Thompson,  B.S.,  Assistant  Animal  Industry,  Davis. 

J.  C.  Bridwell,  B.S.,  Assistant  Entomologist. 
L.  Bonnet,  Assistant  Viticulturist. 

F.  C.  H.  Flossfeder,  Assistant  in  Viticulture,  University  Farm,  Davis. 
P.  L.  Hibbard,  B.S.,  Assistant  Fertilizer  Control  Laboratory. 

C.  H.  McCharles,  M.S.,  Assistant  Agricultural  Chemical  Laboratory. 

B.  A.  Madson,  B.S.A.,  Assistant  Experimental  Agronomist. 
Howard  Phillips,  B.S.,  Assistant  Animal  Industry,  Davis. 

Walter  E.  Packard,  M.S.,  Field  Assistant  Imperial  Valley  Investigation,   El  Centre 
L   M.  Davis,  B.S.,  Assistant  in  Dairy  Husbandry,  University  Farm,  Davis. 
S.   S.  Rogers,  B.S.,  Assistant  Plant  Pathologist,   Plant  Disease  Laboratory,   Whittier. 
H.  A.  Ruehe,  B.S.A.,  Assistant  in  Dairy  Husbandry,  University  Farm,  Davis. 

C.  O.   Smith,  M.S.,  Assistant  Plant  Pathologist,   Plant  Disease  Laboratory,  Whittier. 

E.  H.  Smith,  M.S.,  Assistant  Plant  Pathologist. 

C.  L.  Roadhouse,   D.V.M.,  Assistant  in  Veterinary  Science. 

F.  M.  Hayes,  D.V.M.,  Assistant  Veterinarian. 

M.  E.  Stover,  B.S.,  Assistant  in  Agricultural  Chemical  Laboratory. 

W.  H.  Volck,  Field  Assistant  in  Entomology,  Watsonville. 

E.  L.  Morris,  Field  Assistant  in  Entomology,  San  Jose. 

E.  E.  Thomas,  B.S.,  Assistant  Chemist,  Plant  Disease  Laboratory,  Whittier. 

A.  B.  Shaw,  B.S.,  Assistant  in  Entomology. 

G.  P.  Gray,  M.S.,  Chemist  in  Insecticides. 

H.   D.  Young,  B.   S.,  Assistant  in  Agricultural  Chemistry,   Plant  Disease  Laboratory, 

Whittier. 
A.  R.  Tylor,  B.S.,  Assistant  in  Plant  Pathology,  Plant  Disease  Laboratory,  Whittier. 
L.  T.  Sharp,  B.S.,  Assistant  in  Soils. 
W.  W.  Cruess,  B.S.,  Assistant  in  Zymology. 
J.  F.  Mitchell,  D.V.M.,  Assistant  in  Veterinary  Laboratory. 
W.  B.  Boys,  Assistant  Cerealist. 
M.  E.  Holter,  B.S.,  Assistant  Soil  Chemist. 

Anna  M.  Lute,  Scientific  Assistant,  United  States  Department  of  Agriculture. 
J.  C.  Roper,  Patron,  University  Forestry  Station,  Chico. 
E.  C.  Miller,  Foreman,  Forestry  Station,  Chico. 

D.  L.  Bunnell,  Secretary  to  Director. 


NEW  CONTROL  METHODS 


FOR    THE 

PEAR  THRIPS  AND  PEACH  TREE  BORER. 

By  Earl  L.  Morris. 

[Introductory  Notes. — The  present  Bulletin  gives  the  practical  results  of  studies 
on  the  two  most  serious  pests  in  the  Santa  Clara  Valley.  They  were  conducted  by 
Mr.  Morris  under  the  auspices  of  the  Experiment  Station.  Very  decided  progress 
was  made  towards  the  control  of  these  insects,  both  of  which  extend  into  other  parts 
of  the  State  and  are  causing  much  concern  at  the  present  time. — C  W.  Woodworth.] 

LIME    SPRAY    FOR    THRIPS    (Euthrips    pyri). 

This  paper  is  based  on  an  experiment  in  a  pear  orchard  belonging 
to  W.  C.  Bogen  on  San  Tomas  Road,  near  San  Jose,  California.  It  was 
possible  to  make  this  experiment,  which  extended  over  two  seasons, 


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Fig.    1. — Whitewashed    tree    coming   out    into    full    bloom. 


368 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION. 


solely  through  the  hearty  cooperation  of  Mr.  Bogen,  who  at  all  times 
gave  freely  of  his  time,  money  and  counsel. 

The  period  covers  the  fruiting  season  of  1910  and  1911.  The  writer 
had  observed  that  in  some  instances  pear  trees  sprayed  with  a  heavy 
solution  of  home-cooked  lime-sulphur,  which  contained  a  large  excess 
of  lime,  were  freer  from  attacks  of  thrips  than  pear  trees  in  the  same 


Fig.   2. — Unsprayed  trees  at  blossoming  time.     This  tree  is  adjacent  to  the  one  shown 

in  figure  1. 

orchard  which  were  not  sprayed.  From  previous  experiments  it  seemed 
highly  improbable  that  sulphur  in  chemical  combination  with  the  lime 
was  the  active  agency.  The  only  other  possible  agency  was  the  free 
lime  which  was  sufficient  to  make  a  thin  whitewash.  Acting  on  the 
above  suggestion  in  the  spring  of  1910,  we  sprayed  four  rows  of  pear 
trees,  thirty-one  trees  in  a  row,  and  three  trees  on  each  of  the  next 


Bulletin  228]  pear  THRIPS  AND  PEACH  TREE  BORER.  369 

two  rows,  making  in  all  one  hundred  thirty  trees.  This  was  six  trees 
more  than  one  sixth  of  the  orchard,  and  the  adjacent  unsprayed  trees 
made  an  excellent  check.  The  application  was  made  with  a  hand  pump, 
without  constant  agitation,  with  the  result  that  the  last  whitewash 
sprayed  from  the  tank  was  much  thicker  than  the  first.  The  last  trees 
sprayed,  especially  the  last  six,  which  were  in  unsprayed  rows,  were 
covered  with  a  very  thick,  heavy  whitewash.  This  application  was  made 
when  very  few  blossom  buds  were  open  sufficiently  to  admit  the  thrips. 
At  the  time  of  full  blossom  it  was  very  apparent  that  the  number  of 
blossoms  was  in  direct  proportion  to  the  amount  of  whitewash.  The 
trees  which  had  a  thin  coating  of  whitewash  had  very  few  blossoms ; 
those  which  had  a  very  thick  coating  of  whitewash  had  abundance 
of  blossoms.  Fig.  1  shows  thickly  whitewashed  trees  in  full  bloom. 
Fig.  2  shows  adjacent  unsprayed  trees  with  very  few  blossoms,  the 
blossom  buds  having  been  destroyed  by  the  thrips.  The  amount  of 
fruit  corresponded  to  the  amount  of  blossom. 

The  season  of  1911  the  experiment  was  repeated  on  a  larger  scale. 
Between  one  and  two  weeks  before  the  time  for  the  buds  to  open, 
Mr.  Bogen  sprayed  a  large  number  of  trees  very  thoroughly  with  thick 
whitewash.  Time  is  a  great  factor  in  the  control  of  thrips,  and  we 
had  hoped  to  show  from  this  experiment  that  the  whitewash  would 
have  the  same  beneficial  effect  when  applied  a  week  or  more  before  the 
buds  open  as  when  applied  at  the  time  of  opening  An  exceedingly 
heavy  downpour  of  rain  washed  the  lime  from  the  buds  and  defeated 
our  plans.  By  the  time  the  orchard  was  again  dry  enough  for  spray- 
ing, the  buds  were  just  beginning  to  open  and  conditions  were  ripe  for 
duplicating  the  experiment  of  the  previous  season. 

About  one  half  of  the  orchard  was  used  for  the  experiment.  It  con- 
sisted, including  checks  and  sprayed  trees,  of  seven  rows,  thirty-six 
trees  to  the  row.  The  same  material  was  used  as  in  the  previous  experi- 
ment. Two  rows  were  sprayed,  one  row  unsprayed,  two  sprayed,  two 
unsprayed,  with  this  exception,  that  in  the  one  unsprayed  row  of  trees 
seven  trees  were  sprayed  by  mistake. 

The  results  were  the  same  as  the  previous  year.  All  the  sprayed 
trees,  including  the  seven  in  the  unsprayed  row,  came  into  full  blossom. 
The  unsprayed  trees  blossomed  very  feebly.  The  fruit  corresponded 
very  closely  to  the  blossoming.  The  sprayed  trees  averaged  eight  times 
as  much  fruit  as  the  unsprayed  trees.  Fig.  3  shows  sprayed  and 
unsprayed  trees  at  picking  time.  Fig.  4  shows  the  fruit  from  a  sprayed 
and  an  unsprayed  tree. 

We  used  eighty  (80)  pounds  of  quicklime  for  one  hundred  (100)  gal- 
lons of  spraying  material.  The  whitewash  was  strained  through  one 
fourteenth  (1/14)  inch  mesh  wire  screen  and  the  same  sized  screen  used 
on  the   suction  hose   of  the   pump.      The   ordinary   Bordeaux   nozzles 


370  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STAT 


ION, 


Fig.   3. — Trees   at   harvest   time  ;    the   lower   one  was   whitewashed   and   carries   fruit. 


BULLETIN  22S]  PEAR   THRIPS  AND   PEACH    TREE   BORER.  371 

worked  well.  But  it  was  necessary  to  enlarge  slightly  the  opening  in  the 
disks  of  Vermorel  type  nozzles.  We  found  it  very  important  to  have 
the  lime  properly  slaked.  Good  lime  properly  slaked  is  of  creamy  con- 
sistency, with  a  negligible  amount  of  grit.  It  forms  a  smooth,  uniform, 
creamy  coating  on  the  tree.  An  attempt  to  use  improperly  slaked  lime 
will  usually  result  in  complete  failure.  No  amount  of  written  instruc- 
tion will  teach  one  to  slake  lime.  The  knowledge  must  come  from  actual 
work  with  some  one  who  has  had  the  experience. 

In  orchard  practice  we  found  it  convenient  to  have  our  slaking  vat, 
which  was  6  by  4  by  1  feet,  elevated  about  three  feet,  with  one  end 
slightly  lower  than  the  other.  In  the  lower  end  we  arranged  a  sliding 
door  through  which  the  whitewash  flowed  by  gravity  into  a  containing 


(Unsprayed. )  (Whitewashed. ) 

Fig.  4. — Fruit  at  harvest  from  treated  and  untreated  trees. 

vat.  The  lower  vat  was  shorter,  narrower,  and  deeper  than  the  slaking 
vat  to  facilitate  the  removal  of  the  material  to  the  spray  tank.  Between 
the  two  vats  we  arranged  a  piece  of  window  screen,  of  one  fourteenth 
inch  mesh,  supported  by  chicken  fencing,  through  which  the  whitewash 
passed  in  flowing  from  the  slaking  vat. 

The  cost  of  material  ranges  from  one  (1)  to  one  and  one  half  (1J) 
cents  per  gallon,  depending  upon  the  cost  of  lime  and  labor.  One 
application  proved  sufficient  to  protect  the  blossoms  and  permit  setting 
of  fruit.  We  did  not  find  it  necessary  to  spray  a  second  time  for  larvge, 
although  in  the  first  experiment  enough  larvse  appeared  to  lead  us  to 
believe  that  in  some  cases  a  second  spraying  would  be  necessary  with 
some  good  contact  spray. 


372 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION. 


ASPHALTUM   TREATMENT   FOR  THE   PEACH   TREE    BORER. 

The  western  peach  tree  borer  (Sanninoidea  pacifica)  is  an  insect 
of  much  economic  importance  in  the  horticultural  district  about  the 
southern  arm  of  San  Francisco  bay. 

The  investigations  upon  which  this  paper  is  based  were  made  in 
most  part  in  the  peach  orchard  of  the  J.  H.  Flickinger  Company, 
Berryessa,  California.  They  have  extended  over  a  period  of  four  years. 
The  results  have  not  been  verified  for  other  districts. 

The  adult  borers  are  slender,  blue-black,  day-flying  moths,  about  one 
inch  long.  They  are  seldom  seen  and  very  rarely  recognized  by  the 
orchardists.    They  issue  more  or  less  from  February  to  September,  but 


Fig.  5. — Work  of  the  peach  tree  borer. 

the  mass  of  them  appear  about  the  middle  of  July.  They  place  the  eggs 
on  the  trunk  of  the  tree  from  the  ground  up  two  feet,  one  to  twenty-five 
eggs  in  a  place.  These  are  very  small  and  generally  escape  notice.  They 
hatch  in  a  few  days. 

The  newly  hatched' larvae,  or  " worms,"  which  are  difficult  to  find, 
usually  enter  the  bark  at  or  near  the  ground.  The  new  burrow  is 
marked  at  first  by  light  brown  bark  dust,  which  in  a  few  hours  dis- 
appears, after  which  it  is  nearly  impossible  to  find  the  opening.  The 
larvaa  grow  rapidly,  work  their  way  through  the  bark,  and  spend  most 
of  their  life  between  the  bark  and  wood,  where  they  may  do  great 


Bulletin  228] 


PEAR    THRIPS   AND    PEACH    TREE    BORER. 


373 


damage  by  boring  long  distances,  often  completely  girdling  the  trees. 
Gum  flows  as  a  result  of  this  injury  and  is  a  fairly  reliable  indication 
of  the  presence  of  the  large  "worms."  Unfortunately  there  is  nothing 
to  show  the  presence  of  the  small  "worms." 

The  full-grown  larvae  are  about  one  inch  long  and  the  diameter  of  a 
slate  pencil.  They  have  white  bodies  and  dark  brown  heads.  When 
ready  to  pupate,  they  seek  places  from  which  the  moths  can  easily 
issue  and  construct  about  themselves  cocoons  from  the  chewed-up  wood 
and  bark.  The  cocoons  are  light  brown  capsule-shaped  bodies,  slightly 
larger  than  the  "worms."  They  may  be  found  under  the  bark,  in  the 
bark,  or  in  the  ground  an  inch  or  more  from  the  tree. 

The  usual  method  of  combating  the  peach  borer  is  to  dig  out  the 
"worms"  during  the  winter  season,  but  often  the  knife  causes  more 
damage  than  the  borers,  especially  if  the  digging  must  be  done  con- 


Fig.   6. — The  asphaltum  treatment  for  the  peach  tree  borer. 

secutive  years  or  by  careless  workmen.  In  the  fall  the  soil  is  removed 
from  the  base  of  the  tree  to  a  depth  of  six  or  eight  inches  and  the  borers 
dug.  In  the  spring  they  are  dug  again  and  the  soil  replaced.  The 
second  digging  is  necessary  because  in  the  fall  many  of  the  "worms"  are 
too  small  to  be  found. 

Many  preparations  are  being  used  on  the  trunks  of  trees;  some  to 
keep  the  moths  from  depositing  eggs,  some  to  prevent  the  "worms" 
from  entering,  some  to  kill  the  ' '  worms ' '  after  they  have  entered.  None 
of  these  have  been  wholly  satisfactory.  Experiments  along  these  lines 
by  the  writer  led  to  the  use  of  hard  asphaltum,  grades  "C"  and  "D," 
with  good  results.  This  was  applied  early  in  the  spring  to  badly  infested 
trees  from  which  the  borers  had  not  been  dug.  It  was  found  that  a 
thick  heavy  coating  prevented  both  the  issuance  and  the  entrance  of 
about  95  per  cent  to  98  per  cent  of  the  insects,  the  degree  of  efficiency 
depending  upon  the  thoroughness  of  the  application.    Asphaltum  does 


374  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

not  penetrate,  crack,  deteriorate,  or  bind  the  tree,  since  it  yields  to  the 
slightest  pressure.  Four  years  of  experimenting  have  not  shown  the 
least  injury. 

The  material  is  applied  warm  with  a  brush  from  five  inches  below 
to  five  inches  above  the  ground.  It  is  easier  to  apply  two  or  more  coat- 
ings than  to  try  to  put  on  more  at  one  time  than  will  adhere  firmly.  The 
first  coating  will  harden  very  quickly  and  the  second  can  be  applied 
without  loss  of  time.  Two  coatings  are  generally  sufficient  unless  the 
bark  is  very  rough.  But  in  any  case  a  thick,  uniform  covering  is  abso- 
lutely necessary  for  the  best  results. 

Borers  are  seldom  uniformly  distributed  over  an  orchard.  Small 
blocks  of  trees  here  and  there  may  be  badly  infested  and  the  most  of 
the  orchard  comparatively  free  from  the  pest.  In  such  cases  it  is  not 
necessary  to  treat  all  of  the  trees  with  asphaltum,  but  it  is  necessary  to 
examine  them  carefully,  for  in  no  other  way  can  the  true  conditions 
be  known. 

A  convenient  way  to  handle  the  asphaltum  is  to  mount  an  iron  kettle 
on  the  running  gear  of  an  orchard  truck  and  suspend  beneath  it  a  sheet- 
iron  apron  as  a  fire  box.  Keep  hard  asphaltum  in  the  kettle  all  the  time 
so  that  the  melted  asphaltum  will  not  get  too  hot  to  carry  in  small  con- 
tainers and  apply  directly  to  the  trees. 

We  have  also  used  asphaltum  to  a  limited  extent  for  covering  wounds 
and  for  grafting.  And  although  our  experiments  are  not  completed,  we 
believe  it  may  become  very  useful  as  a  dressing  for  tree  surgery. 

SUMMARY. 

In  the  fall  throw  the  soil  away  from  the  trees  and  dig  the  borers.  In 
the  spring  dig  the  borers  again  and  apply  a  thick  coating  of  asphaltum 
and  replace  the  soil.  Examine  the  trees  each  subsequent  year  to  remove 
borers  and  to  repair  any  thin  or  broken  places  in  the  asphaltum  coating. 


STATION    PUBLICATIONS    AVAILABLE    FOR    DISTRIBUTION. 

REPORTS. 

1896.  Report  of  the  Viticultural  Work  during  the  seasons  1887-93,  with  data  regard- 

ing the  Vintages  of   1894-95. 

1897.  Resistant  Vines,  their  Selection,  Adaptation,  and  Grafting.     Appendix  to  Viti- 

cultural Report  for  1896. 

1902.  Report  of  the  Agricultural  Experiment  Station  for  1898-1901. 

1903.  Report  of  the  Agricultural  Experiment  Station  for  1901-03. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment  Station  for  1903-04. 


BULLETINS. 


Reprint.  Endurance  of  Drought  in  Soils  of 

the  Arid  Regions. 
No.   128.  Nature.  Value,  and  Utilization  of 

Alkali  Lands,  and  Tolerance  of 

Alkali.      (Revised  and  Reprint, 

1905.) 
133.  Tolerance    of   Alkali    by   Various 

Cultures. 
147.  Culture  work  at  the  Sub-stations. 
162.  Commercial  Fertilizers.      (Dec.  1, 

1904.) 

167.  Manufacture    of    Dry    Wines    in 

Hot  Countries. 

168.  Observations  on  Some  Vine  Dis- 

eases in  Sonoma  County. 

169.  Tolerance  of  the  Sugar  Beet  for 

Alkali. 

170.  Studies   in    Grasshopper    Control. 

171.  Commercial     Fertilizers.        (June 

30,  1905.) 
174.  A  New  Wine-cooling  Machine. 

176.  Sugar  Beets  in  the  San  Joaquin 

Valley. 

177.  A   New    Method   of   Making   Dry 

Red  Wine. 

178.  Mosquito  Control. 

179.  Commercial    Fertilizers.       (June, 

1906.) 

181.  The  Selection  of  Seed- Wheat. 

182.  Analysis     of     Paris     Green     and 

Lead     Arsenic.      Proposed     In- 
secticide Law. 

183.  The  California  Tussock-moth. 

184.  Report   of  the   Plant   Pathologist 

to  July  1,  1906. 

185.  Report  of  Progress  in  Cereal  In- 

vestigations. 

186.  The   Oidium  of  the  Vine. 

187.  Commercial    Fertilizers.       (Janu- 

ary,  1907.) 

188.  Lining  of  Ditches  and  Reservoirs 

to  Prevent  Seepage  and  Losses. 

189.  Commercial    Fertilizers.       (June, 

1907.) 

190.  The  Brown  Rot  of  the  Lemon. 

191.  California  Peach  Blight. 

192.  Insects  Injurious  to  the  Vine  in 

California. 

193.  The  Best  Wine  Grapes  for  Cali- 

fornia ;    Pruning  Young  Vines ; 
Pruning  the  Sultanina. 

194.  Commercial     Fertilizers.        (Dec, 

1907.) 


No.   195. 
197. 


198. 
199. 
200. 

201. 

202. 

203. 

204. 

205. 

206. 

207. 
208. 
209. 
210. 

211. 

212. 
213. 
214. 
215. 

216. 

217. 
218. 
219. 

220. 

221. 

222. 
223. 
224. 

225. 

226. 

227. 


The  California  Grape  Root-worm. 

Grape  Culture  in  California;  Im- 
proved Methods  of  Wine-mak- 
ing ;  Yeast  from  California 
Grapes. 

The   Grape   Leaf-Hopper. 

Bovine  Tuberculosis. 

Gum  Diseases  of  Citrus  Trees  in 
California. 

Commercial  Fertilizers.  (June, 
1908.) 

Commercial  Fertilizers.  (Decem- 
ber,   1908.) 

Report  of  the  Plant  Pathologist 
to  July  1,   1909. 

The  Dairy  Cow's  Record  and  the 
Stable. 

Commercial  Fertilizers.  (Decem- 
ber, 1909.) 

Commercial  Fertilizers.  (June, 
1910.) 

The  Control  of  the  Argentine  Ant. 

The  Late  Blight  of  Celery. 

The  Cream  Supply. 

Imperial  Valley  Settlers'  Crop 
Manual. 

How  to  Increase  the  Yield  of 
Wheat  in  California. 

California  White  Wheats. 

The   Principles   of   Wine-making. 

Citrus  Fruit  Insects. 

The  House  Fly  in  its  Relation  to 
Public  Health. 

A  Progress  Report  upon  Soil  and 
Climatic  Factors  Influencing 
the  Composition  of  Wheat. 

Honey   Plants  of  California. 

California  Plant   Diseases. 

Report  of  Live  Stock  Conditions 
in  Imperial  County,   California. 

Fumigation  Studies  No.  5  ;  Dos- 
age Tables. 

Commercial  Fertilizers.  (Oct. 
1911.) 

The  Red  or  Orange  Scale. 

The  Black  Scale. 

The  Production  of  the  Lima 
Bean. 

Tolerance  of  Eucalyptus  for 
Alkali. 

The  Purple  Scale. 

Grape  Vinegar. 


CIRCULARS. 


No.     1.  Texas  Fever. 

7.  Remedies  for  Insects. 
9.  Asparagus  Rust. 

11.  Fumigation  Practice. 

12.  Silk  Culture. 

15.   Recent    Problems    in    Agriculture. 
What  a  University  Farm  is  For. 
19.  Disinfection   of   Stables. 

29.  Preliminary    Announcement    Con- 

cerning Instruction  in  Practical 
Agriculture  upon  the  Univer- 
sity Farm,  Davis,  Cal. 

30.  White   Fly  in  California. 

32.  White  Fly  Eradication. 

33.  Packing    Prunes    in    Cans.      Cane 
Sugar  vs.  Beet  Sugar. 

Analyses    of    Fertilizers    for    Con- 
sumers. 

Instruction    in    Practical    Agricul- 
ture at  the  University  Farm. 
4  6.   Suggestions   for   Garden   Work   in 
California  Schools. 

Butter  Scoring  Contest,   1909. 

Fumigation  Scheduling. 


36 


3  9 


IS. 
50. 


No.  52.  Information  for  Students  Con- 
cerning the  College  of  Agricul- 
ture. 

55.  Farmers'  Institutes  and  Univer- 
sity   Extension    in    Agriculture. 

58.  Experiments  with  Plants  and 
Soils  in  Laboratory,  Garden, 
and  Field. 

60.  Butter  Scoring  Contest,   1910. 

61.  University  Farm  School. 

62.  The  School  Garden  in  the  Course 

of  Study. 

63.  How     to     Make     an     Observation 

Hive. 

64.  Announcement   of  Farmers'    Short 

Courses  for  1911. 

65.  The  California  Insecticide  Law. 

66.  Insecticides  and  Insect  Control. 

67.  Development  of  Secondary  School 

Agriculture    in    California. 

68.  The  Prevention  of  Hog  Cholera. 

69.  The    Extermination    of    Morning- 

Glory. 

70.  Observations    on     the     Status     of 

Corn-growing  in  California. 


13   2 G  4 i 


